Lawn mower



Q Oct. 28, 1930. c. A. GRATloT 1,779,699

LAWN MOWER Original Filed Dec. l5, 1927 y Zena/' Grazingelttouwq from damage by stones or other hard obj ects Patented Oct. 28, 1930 UNITED sTATEs CHESTER A. GRATIOT, F PORTLAND, oREGoN, Ass'iGNon'QslY MESNE AssiGNME-NTSQTO l EvERsHARr LAWNMOWER COMPANY, AooRroRATToNoF NTWADAV n' y LAWN Mow'nn g Application led December 15, 1927, Serial No. 240,195. Renewed March 17, 1930.v

The'principal object of my invention is ,to protect the revolving cutters of a lawn mower accidentally coming in contact therewith.

yA second object is to protect thepositive Vgearing serving to drive the rotary cutters n from damagevoccasioned by the sudden stopping of the cutters. Y

@ther objects and advantages of my `invention, and objects relating to detailsof con! struction and arrangements of parts, will be readily apparent in thecourse of the detailed Y description to follow.

The accompanying drawings illustrate by way of example a preferred form of my in-l vention, in which :V Y

Figure l is a view in perspective of the entire lawn mower.

Fig. 2 is a fragmentary view in axial section of one end of the cutter head showing the manner of attachment thereof to the cutter head shaft.

Referring to said views, the reference numeral 1 indicates two ytraction wheels. A spindle or shaft 2 is driven by a cog wheel gear from the traction wheels in the usual manner. yThe cutter head 3Y is fitted to the spindle 2 so that it is freezto either V rotate or slide axially thereon. Y

i Two coil springs-5 and 6 disposed upon the spindle 2 are similarly attached to the spindle 2 and cutter head 3 to drive the latter in rotary motion vand constrain it to a medial pocutter head before the coils of one `spring or the other are fully compressed.y f

The cutter head being virtually free upon the shaft with a certain Yamplitude of movement permitted by the springs may stop momentarily4 or similarly lexceed the rotative speed. of the spindle.

Upon coming in contact with a sto-ne or otherhard object' the cutter head will be tum of the cutter head into an `endwise or axial thrust due tothe spiral shapejof the cutters. Thismovement' of the Vcutter head axv ially will tend to roll the stonebetween the spirall cutter and the lstationary rectilinear blade and tend to dislodgethe obstacle. v

Itv will be observed vthat a great portion of the work expended by the suddenly retarded cutter head is dissipated in axial ,oscillationsVlr f of the cutter headupon the spindle rather than in disarranging the kalignmentof the Vcutters asis usual when the cutter head is inflexibly driven. l Y

From the foregoingI description, taken in connection withk the accompanying drawings,

the advantages ofthe lconstruction and apvplication Vof my improved lawn mowers will bejreadily apparent; butLwhile I have vdescribed the principle of operationof the invention,'together with the devices I now consider the best embodiment thereof,itwill be readily understood that the structures shownv are merely illustrative and that such changes claim, is

revolve in Contact with a stationary knife, a

liiexible cutter head drivin'g'mechanism comprising a driving spindle, a cutter head'looseand' rotative relation, and two oppositely disposed helical springs surrounding Vsaid splndle attached atthe inner ends' to the said;

-may be made therein as will lie within the v Lscope ofthe following claims. 'i i Having described my invention,Y what I 1 r 1. In lawn mowers employing a cutter head composed of kcutters the edgesk ofwhich-are spirallypdispo'sed, and whichfis arranged tov f ly mounted thereon with respect to both axial.

spindle and to the said cutter head at the outer ends to yieldingly maintain said outter-head in medial position on said spindle.

position 'on said spindle.`

2. In lawn mowers employing a cutter head the cutting edges of which are spirally disposed, and which is arranged to revolve against a stationary knife, a flexible cutter head driving mechanism comprising a driving spindle, a cutter head loosely fitted to said spindle, and a pair of helical springs oppositely disposed upon said spindle and secured rotatively therewith 'at one jendand to the cutter head on the other end to yieldingly maintain lsaid `cutter-head in medial A. GRATIOT.

^ STER 

